1. Field of the Invention
The invention relates to slide fasteners, and particularly, to woven slide fasteners employing spaced coupling elements continuously molded on connecting threads to form coupling element trains which are attached to edges of the support tapes by loops of the tape weft thread passing around the connecting threads between the elements.
2. Description of the Prior Art
U.S. Pat. No. 3,328,857 discloses a fastener stringer with a pair of cords and plastic fastener elements molded to the cords with sections of the cords covered by molded plastic material in alternate and staggered spaces between the leg portions of adjacent elements, the filling threads of a woven tape passing over the cords as well as warp threads of the tape between opposite leg portions of each element; ordinary slide fastener stringer weaving apparatus and techniques cannot be used to interweave filler threads with connecting cords joining leg portions of adjacent coupling elements and further warp threads extending between the opposite leg portions of each coupling element.
In woven slide fastener stringers employing spaced coupling elements molded on the connecting threads wherein the weft thread is looped at an edge of the tape around the connecting threads between the elements to secure the elements to the edge of the tape, the elements tend to twist (i.e. rotate about an axis defined by the edge of the tape) relative to the tape and each other since the connecting threads are very flexible and cannot prevent such twisting of the coupling elements; such twisting often prevents the interlocking of the elements with mating elements of an opposing stringer.
The art also contains, as illustrated in U.S. Pat. No. ;b 3,328,857, No. 3,414,948, No. 3,445,915 and No. 3,696,473, a number of slide fasteners employing spaced coupling elements molded on connecting threads wherein the trains of coupling elements are attached to the edge of the tape by stitches passing over leg portions of the coupling elements. U.S. Pat. No. 3,487,531 discloses the passing of an interwoven warp thread over the leg portions of a coupling element to secure the train of coupling elements to the edge of a tape.